I replaced the float type sender in my bus with a capacitance based sender with no moving parts. It is quite accurate. My VMSpc shows total fuel used and the fuel gauge tracks right along with it.
I know from experience that I can only use 130 gallons out of my 150 gallon tank. My sender is cut off so that empty is at or just above 130 gallons.
The only thing to watch with the capacitance senders is they are susceptible to fungal shorting. Be sure to BIO your tank every now and again.